Process for the conversion of renewable oils to liquid transportation fuels

ABSTRACT

The present invention relates to production of fuels or fuel blendstocks from renewable sources. Various embodiments provide a method of producing a hydrocarbon product by hydrotreating a feedstock including at least one of a renewable triacylglyceride (TAG), renewable free fatty acid (FFA), and renewable fatty acid C 1 -C 5  alkyl ester (C 1 -C 5  FAE) in the presence of a nonsulfided hydrotreating catalyst to produce a first product including hydrocarbons. In some examples, the first product can be subjected to further chemical transformations such as aromatization, cracking, or isomerization to produce a second product including hydrocarbons. In various embodiments, the first or second hydrocarbon product with minimal or substantially no further processing can be suitable as a liquid transportation fuel or fuel blendstock, including fuels such as gasoline, naptha, kerosene, jet fuel, and diesel fuels.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/493,193, filed on Jun. 27, 2009, now U.S. Pat. No.8,247,632, which is a continuation-in-part of U.S. patent applicationSer. No. 12/264,689, filed on Nov. 4, 2008, entitled “PROCESS FOR THECONVERSION OF RENEWABLE OILS TO LIQUID TRANSPORTATION FUELS” (now U.S.Pat. No. 7,989,671), the disclosures of which are herein incorporated byreference.

STATEMENT OF GOVERNMENT SUPPORT

This invention was made with U.S. government support under CooperativeAgreement No. W9132T-08-2-0014 awarded by the U.S. Army ConstructionEngineering Research Laboratory. The government has certain rights inthis invention.

FIELD OF THE INVENTION

The invention relates to a method for the conversion of renewable fatsand oils (triacylglycerides, or TAGs) to hydrocarbons. The inventionalso accommodates the production of hydrocarbons from fatty acid C₁-C₅alkyl esters (C₁-C₅ FAEs) or free fatty acids (FFAs). In some examples,FFAs or C₁-C₅ FAEs can be derived from TAGs. The fats and oils can bederived from biomaterials such as plants, animals, or algae, or mixturesthereof. The method is applicable to the manufacture of liquidtransportation fuels, for example, such as gasoline, naphtha, kerosene,jet, and diesel fuels. The method is also applicable to the manufactureof other hydrocarbons.

BACKGROUND OF THE INVENTION

Increasing costs for petroleum-derived fuels are driving interest inalternative starting materials (feedstocks) for the production of fuels.Additionally, concern over increasing atmospheric carbon dioxide levelshas spawned interest in “carbon-neutral” fuels. One possible solution toboth of these issues is the utilization of TAG feedstocks for theproduction of hydrocarbon-based transportation fuels.

Certain TAGs are already utilized as feedstocks for the production of“biodiesel.” In this process, the TAG is transesterified with methanol,ethanol, or another C₁-C₅ alcohol, to provide a C₁-C₅ FAE and glycerine.The C₁-C₅ FAE is separated, purified, and sold as an additive,supplementing petroleum-derived diesel fuel. C₁-C₅ FAE diesel additivesprovide certain specific benefits to their use (e.g., lubricity), butsuffer serious physical limitations when used as the sole fuel and notas a blendstock (e.g., cold-flow properties).

C₁-C₅ FAE diesel fuel represents a first-generation bio-derived fuel.The shortcomings of this generation of fuel are directly related to thefuel-possessing oxygen functionality. A second-generation fuel possessesno oxygen functionality, providing a more petroleum-like product withrespect to elemental composition, and is oftentimes termed “renewablediesel.”

Recent publications and patents have described the conversion of TAG tohydrocarbon fuels via technology oftentimes referred to as“hydrodeoxygenation.” This technology converts the fatty acid-portion ofa TAG to a hydrocarbon having the same number of carbons as the fattyacid-portion or to a hydrocarbon possessing one carbon less than thefatty acid-portion. The glycerine portion of the TAG is most oftenconverted to propane or otherwise lost within the process.

The glycerine portion of the TAG possesses economic value in itselfgreater than that of propane and, as such, could be an importanteconomic by-product from an overall process that would provide glycerineas a by-product.

Certain patents list strategies for limiting the acidity of the fuelthat is produced. This can include recycle of the product with freshfeedstock over the catalyst bed and limiting the total acidity of theproduct introduced to the catalyst.

A major difference between a fatty acid and a TAG is the nature of thecarboxyl functionality present in each compound. For the TAG, the acidis present as an ester (carboxylate) functionality. For the fatty acid,the acid is present as a carboxylic acid. It is well established that anester functionality is more easily reduced to a saturated hydrocarbonvia hydrogenation technology than is a carboxylic acid functionality.This limits the amount of fatty acid that can be present in thefeedstock and feedstock blends.

One method describes the conversion of depitched tall oil to a dieselfuel additive (see generally Canadian Patent 2,149,685). The methoddescribes a hydrodeoxygenation process utilizing a hydrotreatingcatalyst. The catalyst is prepared by presulfiding. The sulfided natureof the catalyst can be maintained by adding sulfur to the tall oilfeedstock at a level of 1000 ppm. The doping agent is carbon disulfide.The hydrodeoxygenation conversion is then performed at 410° C. and 1200psi.

Another method describes the preparation of a diesel fuel from avegetable TAG oil (see generally U.S. Patent Application 2007/0010682).The TAG oil is doped with 50 to 20,000 ppm sulfur. Thehydrodeoxygenation step is performed between 580 and 725 psi and 305°and 360° C.

SUMMARY OF THE INVENTION

Accordingly, there is a need for a method of producing paraffinichydrocarbons from a feedstock including at least one of TAGs, FFAs, orC₁-C₅ FAEs without the need for presulfiding the hydrotreating catalystor doping the feedstock with sulfur. There is a need for an efficienthydrotreating process with few or no additional processing steps whereinthe product includes hydrocarbons that can form fuel or fuelblendstocks, wherein the fuel has hydrocarbon chain lengths distributedsimilarly to those in conventional petroleum-derived fuels.Additionally, there is a need for a method that can efficiently reducefatty acids or fatty acid esters to hydrocarbons, with no limitation tothe amount of fatty acids or fatty acid esters that can be present inthe feedstock blend.

In various embodiments, the present invention provides a method ofproducing a hydrocarbon product. The method includes hydrotreating afeedstock comprising at least one of a renewable triacylglyceride (TAG),renewable fatty acid (FFA), renewable fatty acid C₁-C₅ alkyl ester(C₁-C₅ FAE), or a mixture thereof, in the presence of a nonsulfidedhydrotreating catalyst, to produce a first product comprisinghydrocarbons

In various embodiments, the present invention provides a method ofproducing a transportation fuel. The method includes hydrotreating afeedstock comprising at least one of a renewable triacylglyceride (TAG),renewable fatty acid, renewable fatty acid C₁-C₅ alkyl ester (C₁-C₅FAE), or a mixture thereof, in the presence of a nonsulfidedhydrotreating catalyst, to produce a first product comprisinghydrocarbons. The method also includes subjecting the first product toat least one process selected from aromatization, cracking, andisomerization, to produce a second hydrocarbon product selected fromgasoline, naptha, kerosene, jet fuel, and diesel fuels. The renewableTAG, renewable FFA, and renewable C₁-C₅ FAE comprise fatty acid unitsthat have an even number of carbon atoms.

Various embodiments of the present invention provide a method ofproducing a hydrocarbon product. The method includes hydrotreating afeedstock comprising at least one of a renewable triacylglyceride (TAG),renewable fatty acid, renewable fatty acid C₁-C₅ alkyl ester (C₁-C₅FAE), or a mixture thereof, in the presence of a nonsulfidedhydrotreating catalyst, to produce a first product comprisinghydrocarbons the renewable TAG, renewable FFA, and renewable C₁-C₅ FAEcomprise fatty acid units that have an even number of carbon atoms. Inthe first product, a proportion of hydrocarbons with an odd-number ofcarbon atoms, cyclic hydrocarbons, or hydrocarbons with an even-numberof carbon atoms is dependent on an average temperature used during thehydrotreating.

Hydrotreating catalysts are conventionally sulfurized, and availableprocedures describing the use of hydrotreating catalysts describe asulfurization pre-treatment step. Hydrotreating catalysts have generallybeen used to treat petroleum feedstocks that contain sulfur, and sincesulfur content of the catalyst can influence various characteristics ofthe catalyst, conventionally the catalyst is pre-sulfurized to keepcatalyst sulfur levels steady and thus help to ensure a more predictablereaction that is easier to maintain at a steady-state. By notpre-sulfurizing the hydrotreating catalyst, various embodiments of thepresent invention run counter to conventional teachings; further, it hasunexpectedly been found that the use of a non-conventionalnon-sulfurized hydrotreating catalyst has certain advantages over atraditional sulrfurized hydrotreating catalyst, as further describedbelow.

Various embodiments of the present invention can provide certainadvantages over other methods of generating hydrocarbons. In someembodiments, the present method can provide hydrocarbon fuels or fuelblendstocks having similar properties to petroleum-derived fuels or fuelblendstocks. In various embodiments, the present method can providefuels or fuel blendstocks at lower cost and greater efficiency thanother methods. In various embodiments, the present method can allow theuse of a greater variety of biomaterials for conversion to hydrocarbonssuitable for fuels or fuel blendstocks than other methods. For example,embodiments of the present invention can avoid the use of sulfur-dopingin the feedstock, or can avoid the use of sulfurized catalyst. The useof a nonsulfided catalyst can allow for more efficient usage ofhydrogen; therefore, in various embodiments, less total hydrogen issupplied to the hydrodeoxygenation reactor than is required bytechnologies employing sulfided catalysts or technologies employingsulfur-doped feedstocks. Embodiments of the present method offeradvantages over methods in that the very nature of the catalyst isdifferent, thus potentially offering the ability to operate at lowertemperatures or pressures while achieving the same or superior outcomeas other methods, offering for example economic advantages inlarge-scale production settings. In some embodiments, a nonsulfidedhydrotreating catalyst allows for reduction, decarbonylation, anddecarboxylation reactions to occur over a range of conditions that isbroader than other methods. Various embodiments provide a method thatcan provide efficient reduction of fatty acids to hydrocarbons, with noor little limitation to the amount of fatty acids that can be present inthe feedstock blend. In some examples, feedstock can be advantageouslyconverted to a paraffinic product at lower temperatures and pressuresthan those described previously. In various embodiments, by controllingthe product mixture proportion of hydrocarbon compounds havingodd-numbers of carbon atoms to hydrocarbon compounds having even-numbersof carbon atoms, the range of carbon atoms in the product can be morefinely controlled than other methods, in some examples more efficientlyand with less energy or cost expenditure than other methods. By havinggreater control over the range of carbon atoms in the product, themethod can produce products that more closely adhere to specificationsfor fuels or fuel blendstocks than those produced by other methods, moreefficiently and with less energy or cost expenditure than other methods.In various embodiments, the product mixture proportion of acyclichydrocarbons to cyclic hydrocarbons can be controlled by varying forexample the temperature or catalyst. In some embodiments, the use of anonsulfided catalyst allows the use of higher temperatures than othercatalysts, which can in some examples allow the formation of more cycliccompounds at greater efficiency during the hydrotreatment step thanother methods. In some embodiments, the catalyst can be varied to form ahigher proportion of cyclic hydrocarbons. By forming greater proportionsof cyclic compounds during the hydrotreatment step, fuels and fuelblendstocks for certain jet fuels, which can sometimes requireparticular distributions of cyclic hydrocarbons, can be more easily andmore efficiently generated than other methods.

BRIEF DESCRIPTION OF THE FIGURES

The drawings illustrate generally, by way of example, but not by way oflimitation, various embodiments discussed in the present document.

FIG. 1 illustrates change in enthalpy versus temperature, according tovarious embodiments.

FIG. 2 illustrates calculated enthalpy versus temperature, according tovarious embodiments.

DETAILED DESCRIPTION Definitions

The term “brown grease” as used herein includes waste vegetable oil,animal fat, grease, and the like, such as trap grease (e.g. greaserecovered from waste water), sewage grease (e.g., from a sewage plant),and black grease. Brown grease from traps and sewage plants aretypically unsuitable for use as animal feed. The term brown grease alsoencompasses other grease having a FFA content greater than 20% and beingunsuitable for animal feed.

The term “yellow grease” as used herein includes for example used fryingoils such as for example those from deep fryers. It also encompasseslower-quality grades of tallow from rendering plants.

Fatty acids can be bound or attached to other molecules, for example asesters in triacylglycerides or phospholipids. When they are not attachedto other molecules, they are known as “free” fatty acids. The uncombinedfatty acids or FFAs can come from the breakdown of a TAG into itscomponents (fatty acids and glycerol). For example, a FFA can break offa TAG through hydrolysis, for example, using steam, chemicals, heat,etc. In the presence of a catalyst (e.g., acid), transesterification ofTAGs with an alcohol such as methanol, ethanol, or another C₁-C₅ alcoholcan provide a C₁-C₅ alkyl ester of a fatty acid, which in some examplesare effective as biodiesel. The FFA in crude vegetable oils can rangefrom about 1% to about 4% (olive oil can include up to about 20%). Theamount of FFA in yellow grease (e.g., recycled cooking oil) generallyranges from about 4% to about 15%. Brown grease (e.g., trap grease) caninclude a FFA composition of about 50% to 100% of raw material.

Here the term “hydrotreatment” as used herein is used to refer to acatalytic process performed in the presence of hydrogen that includesreductive chemical reactions, such as for example reduction ofunsaturated bonds, and reduction of carbon to lesser oxidation statesvia removal of bonds to oxygen or other heteroatoms, including forexample carboxylate reduction, carboxylate decarboxylation, carboxylatedecarbonylation, alkene reduction, reduction of conjugated or aromaticunsaturated bonds, reduction of any carbon-oxygen bond including forexample conversion of glycerine to propane, or other reactions includingcarbon-carbon bond cracking and cycloparaffin formation via cyclization,or cycloparaffin formation via cyclization followed byhydrogenation/saturation of conjugated or non-conjugated C—C bonds, oraromatization. For example, hydrotreatment can include a catalyticprocess whereby oxygen is removed from organic compounds as water(hydrodeoxygenation); sulfur from organic sulfur compounds as dihydrogensulfide (hydrodesulfurization); nitrogen from organic nitrogen compoundsas ammonia (hydrodenitrogenation); and halogens, for example, chlorinefrom organic chloride compounds as hydrochloric acid(hydrodechlorination).

The term “normal alkanes” is used to refer to linear alkanes, such asfor example n-paraffins, which do not contain carbon side chains.

The term “renewable” as used herein refers to non-petroleum derived. Afeedstock can be considered renewable if it contains a proportion ofmaterials derived from non-petroleum sources, for example about 1 wt %,5 wt %, 10 wt %, 20 wt %, 30 wt %, 40 wt %, 50 wt %, 60 wt %, 70 wt %,80 wt %, 90 wt %, 95 wt %, or about 99 wt % of the feedstock can includematerials derived from non-petroleum sources. Likewise, a fuel can beconsidered renewable if it contains a proportion of hydrocarbons derivedfrom non-petroleum sources, for example about 1 wt %, 5 wt %, 10 wt %,20 wt %, 30 wt %, 40 wt %, 50 wt %, 60 wt %, 70 wt %, 80 wt %, 90 wt %,95 wt %, or about 99 wt % of the fuel can include hydrocarbons derivedfrom non-petroleum sources. Non-petroleum sources can include, forexample, any biological source, such as plants, animals, or organismssuch as algae.

The term “virgin” as in for example “virgin TAG” as used herein refersto feedstock material that has not been used after being derived fromits source. For example, TAG-containing fats or oils derived from aplant or animal that have not been used to cook food can be consideredto include virgin TAG.

The term “substantially” as used herein refers to a majority of, ormostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%,98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999%.

The term “blendstock” as used herein refers to a composition that can beblended with any other suitable composition to form a fuel. A blendstockcan form any suitable proportion of the final fuel product, for exampleabout 1 wt %, 5 wt %, 10 wt %, 20 wt %, 30 wt %, 40 wt %, 50 wt %, 60 wt%, 70 wt %, 80 wt %, 90 wt %, 95 wt %, or about 99 wt % of the finalproduct. In some examples, distillation can be used to form distinctblendstocks (e.g. having a particular range of hydrocarbon chain lengthsor particular proportions of certain types of hydrocarbon compounds)from a product mixture, and any number of different distinct blendstocksforms from one or different products can be blended in suitableproportions to form a fuel.

Generally, psi pressures given herein are gauge pressures unlessotherwise indicated.

The term “fuel” as used herein can refer to a hydrocarbon mixture, suchas for example a distillate fuel, jet fuel, diesel fuel, compressionignition fuel, gasoline, spark ignition fuel, rocket fuel, marine fuel,or other fuel, qualifying as such by virtue of having a set of chemicaland physical properties that comply with requirements delineated in aspecification developed and published by ASTM (American Society ofTesting and Materials), European Standards Organization (CEN), and/orthe U.S. Military. In some examples, a fuel can be a liquidtransportation fuel, for example, for surface or air transport. Surfacetransport includes both terra firma and oceanic transport. Fuels of thistype are included, but not limited to, ASTM specifications D975 (DieselFuel Oil), D1655 (Aviation Turbine Fuels), D4814 (Automotive SparkIgnition Fuel); military specifications MIL-DTL-83133G (Turbine Fuel,Aviation, Kerosene Type), MIL-DTL-25576D (Propellant, Rocket GradeKerosene), MIL-DTL-38219D (Turbine Fuel, Low Volatility), MIL-DTL-5624U(Turbine Fuel, Aviation), MIL-DTL-16884L (Fuel, Naval Distillate), andother such specifications for similar fuels.

The term “C₁-C₅ FAE” or “fatty acid C₁-C₅ alkyl ester” designates afatty acid in the form of an ester with a C₁-C₅ normal or branched alkylgroup bound to the non-carbonyl oxygen atom of the carboxyl-group. Insome examples, the C₁-C₅ FAE is fatty acid methyl ester (FAME). In someexamples, the C₁-C₅ FAE is a fatty acid ethyl ester (FAEE).

I. Overview

In various embodiments, the present invention provides a method orprocess by which renewable feedstocks can be converted to gasoline,kerosene, jet fuels, and diesel fractions. Feedstocks can include atleast one of renewable TAG, renewable FFA, and renewable C₁-C₅ FAE.According to some examples, feedstocks are converted to a productincluding paraffinic hydrocarbons without presulfiding of ahydrotreating catalyst and without the feedstock being doped withsulfur. In embodiments, feedstocks are converted to a product includingparaffinic hydrocarbons whereby the hydrocarbon chain lengthdistribution is similar to that of petroleum-derived fuels. Control ofthe process can be achieved by allowing for simultaneous hydrotreatingreactions to occur, such as for example reduction, decarbonylation, anddecarboxylation reactions. Control parameters during the reaction caninclude, for example, the temperature, pressure, and the use of anonsulfided hydrotreating catalyst.

The nonsulfided hydrotreating catalyst allows for hydrotreatmentchemical reactions to run simultaneously over a range of conditions. Inthe hydrotreating, the feedstock is reacted with hydrogen in thepresence of the catalyst at a variety of temperature, pressure, andspace velocity conditions, and is generally converted to hydrocarbons.In some examples, the method allows the feedstock to be advantageouslyconverted to a paraffinic product at lower temperatures and pressuresthan those described previously. In some examples, the first product canbe used directly or with minimal processing to provide fuels or fuelblendstocks. In some embodiments, the paraffinic (first) product withminimal or no processing can further undergo additional chemicalprocessing steps, such as for example isomerization, selective cracking,or aromatization steps, to provide a second product that includes fuelsor fuel blendstocks. In some examples, distinct blendstocks can beprovided via distillation of the second product. In some examples, thesecond product is suitable for use as a fuel or blendstock with minimalor substantially no processing.

In various embodiments, the product formed by the hydrotreatment caninclude for example normal alkanes, saturated hydrocarbons, aromatichydrocarbons, or any combination thereof, and can have any suitableproportions of these components. In some examples, any suitable amountof overlap can occur between normal alkanes and saturated hydrocarbons,for example any suitable proportion of the normal alkanes can besaturated hydrocarbons, and any suitable proportion of the normalalkanes can have any suitable degree of unsaturation. In someembodiments, the proportion of normal alkanes, saturated hydrocarbons,and aromatic hydrocarbons can be controlled to various degrees byvarying particular process variables, for example by suitably varyingthe temperature and pressure conditions, as further described herein.

When suitably blended, the blendstocks from the first or second productcan become drop-in-compatible and fit-for-purpose fuels. The fuels thatcan be directly produced or for which blendstocks can be provided by thefirst or second product can include gasoline, naphtha, kerosene, jet, ordiesel fuels. Additionally, hydrocarbons produced by the process can beutilized for the production of chemicals, including those useful asfeedstocks for the production of polymers, such as polyethylene andpolypropylene. In examples of the method including a hydrotreatment, orin examples including both hydrotreatment and followed by additionaltransformative steps, the product fuels can have chemical compositionssimilar to the hydrocarbons and can be fully fungible withpetroleum-derived fuels. That is, the fuels produced can be identical invirtually all respects to commercially available petroleum-derivedfuels. Advantageously, the first or second product, in some embodimentswith little or no further processing, can be better suited for use as afuel or fuel blendstock than other methods, having hydrocarbon chainlength ranges or product distributions better suited for fuel or fuelblendstock use than those produced by other methods, and being producedwith less consumption of energy or valuable materials than othermethods.

Feedstock

According to some examples in this disclosure, a feedstock including atleast one of TAG, FFA, or C₁-C₅ FAE is hydrotreated. The TAG can beobtained from terrestrial or marine sources. The TAG can includetriacylglycerides derived from any suitable renewable source, includingfor example triacylglycerides derived from plants, triacylglyceridesderived from animals, triacylglycerides derived from algae, orcombinations thereof. The feedstock can further includediacylglycerides, monoacylglycerides, FFAs, or C₁-C₅ FAE andcombinations thereof. The feedstock can include yellow grease, browngrease, or a combination thereof. The feedstock can include a blend offresh (e.g. virgin) TAG and used TAG (e.g., yellow grease or browngrease). According to some examples in this disclosure, the feedstock isnot doped with sulfur. The ratio of the virgin and used TAG in thecomposition of a TAG-containing feedstock can be selected such thathydrotreating produces a desired hydrocarbon product composition.

Fatty acids can be obtained from any suitable source. In some examples,fatty acids can be obtained from TAG. In some examples, fatty acids canbe obtained from commercial sources, such as fatty acids marketed asproducts intended for a variety of uses, including cosmetics, or such asfatty acids from waste recovery operations. The quality of the fattyacid to be used in the process, as with any component of the feedstock,can be any suitable quality, and can vary widely. The process is robustenough to accommodate fatty acids possessing varying types ofimpurities, including water. In various examples, the purity of thefatty acids utilized prior to formation of the feedstock can be about 60wt % to 100 wt %, or about 70 wt % to about 95 wt %, or about 88 wt %.The purity of the fatty acid or any other component of the feedstock canbe any suitable purity such that acceptable results are achieved, e.g.such that the method provides hydrocarbons with acceptable quality foruse as transportation fuel or fuel blendstock. Mixtures can possess anysuitable acid number or saponification value. In some examples, the acidnumber or saponification value can be about 0.1 mg KOH/g to about 500,or about 10 to about 400, or about 50 to about 350, or about 100 toabout 300, or about 150 to about 250, or about 190 to about 210 mgKOH/g. In one example, fatty acids suitable for use in the process canhave an acid number of about 201 mg KOH/g and a saponification number ofabout 203 mg KOH/g.

C₁-C₅ FAE can be obtained from any suitable source. In some examples,C₁-C₅ FAE is obtained via transesterification of TAG, or viaesterification of FFA. In some examples, C₁-C₅ FAE can be obtained fromcommercial sources. In some examples, the C₁-C₅ FAE can include B99biodiesel.

In some embodiments, the feedstock can include predominantly TAGs withlittle or no FFAs or C₁-C₅ FAEs. In some embodiments, the feedstock caninclude TAGs and fatty acids. In some embodiments, the feedstock caninclude TAGs and C₁-C₅ FAEs. In some embodiments, the feedstock caninclude fatty acids and C₁-C₅ FAEs. In various embodiments, thefeedstock can include TAGs, C₁-C₅ FAEs, and fatty acids. In someembodiments, the feedstock can include fatty acids with substantiallylittle or no TAGs or substantially little or no C₁-C₅ FAEs. In someembodiments, the feedstock can include C₁-C₅ FAEs with substantiallylittle or no TAGs or substantially little or no FFAs. In someembodiments, the feedstock can include C₁-C₅ FAEs and fatty acids in anysuitable proportion with substantially little or no TAGs.

Feedstock can be Predominantly Fatty Acids, Fatty Acid Esters, or aSuitable Combination Thereof

In various embodiments, the method can convert a feedstock includingpredominantly fatty acids (e.g. substantially no TAGs or C₁-C₅ FAEs) toa mixture of hydrocarbons. In various embodiments, the method canproduce predominantly normal paraffins (e.g. about 51 wt % to about 95wt %, or about 65 wt % to about 85 wt %, or about 70 wt % to about 80 wt%, or about 76 wt %) and iso-paraffins (e.g. about 1 wt % to about 40 wt%, or about 5 wt % to about 30 wt %, or about 10 wt % to about 20 wt %,or about 15 wt %) as well as small amounts of cycloparaffins (e.g. lessthan about 10 wt %, or less than about 5 wt %, or less than about 1 wt%, or about 0 wt %), and olefins (e.g. less than about 15%, or less thanabout 10%, or less than about 5%, or about 3% or less, or less than 1%).In some examples, processing of feedstocks including predominantly fattyacid ester (e.g. substantially no TAGs or C₁-C₅ FAEs) can producesimilar results. In some embodiments, processing of feedstocks includingpredominantly fatty acids and fatty acid esters in any suitableproportion (e.g. substantially no TAGs) can produce similar results.

The product mixture resulting from hydrotreatment of a feedstockincluding fatty acids, C₁-C₅ FAEs, or a suitable mixture thereof, canhave small amounts of fatty acids or fatty acid esters. For example,less than about 10 wt %, 5 wt %, 1%, 0.5%, 0.1%, 0.01 wt %, 0.001 wt %,or less than about 0.0001 wt % fatty acids or fatty acid esters. In someexamples, the amount of fatty acid present can be detected by acid-basetitration techniques, as a readily understood by one of skill in theart. In some examples, the residual fatty acid can be present in anamount such that less than about 5 mg KOH/g hydrocarbon, 1 mg, 0.5 mg,0.3 mg, 0.2 mg, 0.1 mg, 0.01 mg, or less than about 0.001 mg KOHconsumed per gram of hydrocarbon present.

Catalyst

The feedstock is hydrotreated using a hydrotreating catalyst that is notpresulfided. The hydrotreating catalyst can be any nonsulfidedhydrotreating catalyst. In embodiments, the hydrotreating catalyst is anonsulfided hydrogenation catalyst. The hydrotreating catalyst caninclude one or more metals from Groups 6, 8, 9, and 10 of the periodictable of the elements. In some examples, the one or more metals can beselected from palladium (Pd), platinum (Pt), nickel (Ni), andcombinations thereof. In embodiments, the catalyst is anickel-molybdenum (NiMo) catalyst including nickel and molybdenum. Insome embodiments, the catalyst is a cobalt-molybdenum (CoMo) catalyst.The hydrotreating catalyst can include supported or unsupported metals.In various embodiments, the catalyst includes a support. Inapplications, the support includes alumina, silica, or a combinationthereof. The catalyst can be a supported NiMo or CoMo catalyst. Inembodiments, NiMo/Al₂O₃—SiO₂ or CoMo/Al₂O₃ catalyst is utilized. In someembodiments, a Ni catalyst is utilized. In some embodiments, amolybdenum catalyst is utilized. In some embodiments, a catalyst withany suitable proportion of Ni and Mo is utilized.

Catalysts having any suitable type or combination of active sites orstructures can be used as the hydrotreating catalyst. In variousexamples, catalysts with type I active sites or structures can beutilized; in other examples, catalysts without type II active sites orstructures can be utilized. In various examples, catalysts with type IIactive sites or structures can be utilized; in other examples, catalystswithout type II active sites or structures can be utilized.

The use of a nonsulfided catalyst allows for more efficient usage ofhydrogen; therefore, less total hydrogen can be supplied to thehydrodeoxygenation reactor than is required by technologies employingsulfided catalysts.

General Hydrotreatment Conditions

Reactor temperature parameters can vary between about 150° C. and about800° C., or about 250° C. to about 600° C., or about 300° C. to about550° C., or about 340° C. to about 530° C. Reactor pressures can varybetween about 100 psi to about 1000 psi, or about 200 psi and about 750psi. In some embodiments, reactor pressures can vary between about 500psi and about 1000 psi, while in some embodiments, reactor pressures canvary between about 100 psi and about 500 psi. Hydrogen flow rates canvary between about 2.5 standard cubic feet per liter and about 50standard cubic feet per liter of TAG, FFAs, and C₁-C₅ FAEs, or about15-20 standard cubic feet per liter. Liquid hourly space velocities(LHSV) can vary between about 0.1 reactor volumes/hr (e.g. hr⁻¹) and 8hr⁻¹, about 0.5 hr⁻¹ and about 4 hr⁻¹, or between about 0.8 hr⁻¹ andabout 1.2 hr⁻¹ being most preferred.

II. First Product Including Predominantly Normal Alkanes

In various embodiments, a product including predominantly normal alkanesis produced via the hydrotreating step. In some embodiments, the productincluding predominantly normal alkanes can include aromatic hydrocarbonsalong with saturated hydrocarbons. The product including predominantlynormal alkanes can overlap with the product described below includingaromatic hydrocarbons along with saturated hydrocarbons to any degree.For example, any proportion of the normal alkanes in such a productmixture can be saturated hydrocarbons, such as more than about 95 wt %,90 wt %, 80 wt %, 70 wt %, 60 wt %, 50 wt %, 40 wt %, 30 wt %, 20 wt %,or more than about 10 wt % of the product mixture. In other embodiments,less than about 10 wt %, 5 wt %, or less than about 1 wt % of the normalalkanes can be saturated hydrocarbons.

In embodiments, the hydrotreating of the feedstock can be performed atmodest temperatures and pressures (relative to other methods). Invarious embodiments, the temperature is in the range of about 340° toabout 410° C. In some embodiments, the temperature is in the range ofabout 390° to about 410° C. In some embodiments, the temperature isabout 400° C. Preferred pressures in such applications are in the rangeof about 100 psig to 200 psig. In some embodiments, the pressure is inthe range of about 150 psig to about 200 psig. In embodiments, thetemperature is about 400° C., and the pressure is about 200 psig.Suitable pressures can include pressures that are below that typicallyemployed in processes utilizing sulfided hydrotreating catalysts. Insome embodiments, the hydrotreating of the feedstock can be performed atany suitable temperature and pressure, such as any temperature orpressure given in the present paragraph, or any temperature or pressurebetween the ranges given in the present paragraph and the ranges givenin the section below for first products including saturated hydrocarbonsand aromatic hydrocarbons.

The paraffinic hydrocarbon product produced in this manner can includepredominantly normal alkanes. The product can include, for example, morethan about 50 wt % normal alkanes, more than 60 wt % normal alkanes,more than 70 wt % normal alkanes, or about 75 wt % normal alkanes, ormore than about 80 wt % normal alkanes, or more than about 90 wt %normal alkanes. The product can further include normal alkenes. In someexamples, the product can include about 1 wt % normal alkenes, 3 wt %, 5wt %, 7 wt %, 10 wt %, 13 wt %, 15 wt %, 17 wt % or about 20 wt % normalalkenes. In some embodiments, the paraffinic product can further includea trace of fatty acid or no fatty acid, such as for example not morethan 0.001 wt %, 0.01 wt %, 0.1 wt %, 1 wt %, 2 wt %, or not more than 5wt %. This outcome can be achievable including through the use of thenonsulfided hydrotreating catalyst, thus providing excellent conversionof feedstock to paraffinic product. The paraffinic product can beconvertible to liquid transportation fuels by standardpetroleum-refining and processing methods. For example, the paraffinicproduct can further undergo further chemical processing such as forexample isomerization, cracking, or aromatization steps to providetransportation fuels or fuel blendstocks.

III. First Product Including Saturated and Aromatic Hydrocarbons

In various embodiments, higher pressures can be utilized during thehydrotreating step, producing a product including aromatic hydrocarbonsalong with saturated hydrocarbons. A product mixture including aromatichydrocarbons along with saturated hydrocarbons can overlap with theproduct distribution described above for products containingpredominantly normal alkanes to any suitable degree. For example, theproduct including aromatic hydrocarbons along with saturatedhydrocarbons includes predominantly normal alkanes, or more than about95 wt %, 90 wt %, 80 wt %, 70 wt %, 60 wt %, 50 wt %, 40 wt %, 30 wt %,20 wt %, or more than about 10 wt % normal alkanes. In otherembodiments, the product including aromatic hydrocarbons can includeless than about 10 wt %, 5 wt %, or less than about 1% normal alkanes.The operating temperature for such embodiments can be in the range ofabout 470° C. to 530° C. In some embodiments, the temperature is in therange of about 480° C. to 500° C. In some embodiments, the temperatureis about 480° C. The operating pressure can be in the range of about 650psig to about 1000 psig. In some embodiments, the hydrotreating pressurecan be in the range of about 700 psig to 800 psig. In some applications,the pressure is about 750 psig. In some applications, the temperature isabout 480° C., and the pressure is about 750 psig. In some embodiments,the hydrotreating of the feedstock can be performed at any suitabletemperature and pressure, such as any temperature or pressure given inthe present paragraph, or any temperature or pressure between the rangesgiven in the present paragraph and the ranges given in the section abovefor first products including predominantly normal alkanes. One of skillin the art will readily appreciate that by varying the temperature andpressure conditions between those given in the present paragraph andthose given in the section above for first products includingpredominantly normal alkanes, the proportion of normal alkanes,saturated hydrocarbons, and aromatic hydrocarbons can be accordinglycontrolled or adjusted.

In some embodiments, the feedstock is converted to a product includingpredominantly saturated hydrocarbons and aromatic hydrocarbons. Thesaturated/aromatic hydrocarbon product produced in this manner caninclude predominantly saturated hydrocarbons. The product can includemore than about 50 wt % saturated hydrocarbons, 55 wt %, 60 wt %, 65 wt%, 70 wt %, 75 wt %, 80 wt %, 85 wt %, or more than about 90 wt %saturated hydrocarbons. The saturated/aromatic hydrocarbon product caninclude more than about 5 wt % aromatic hydrocarbons, 10 wt %, 15 wt %,20 wt %, 25 wt %, 30 wt %, 35 wt %, or more than about 40 wt % aromatichydrocarbons. In embodiments, the saturated/aromatic product furtherincludes alkene hydrocarbons. The product can include less than about 30wt % normal alkenes, 25 wt %, 20 wt %, 15 wt %, 10 wt %, 5 wt %, 3 wt %,or less than about 1 wt % normal alkenes.

The composition of the feedstock can be selected such that the ratios ofsaturated hydrocarbons to aromatic hydrocarbons to olefinic hydrocarbonsare suited to the production of a desired fuel or fuel blendstock. Forexample, such a saturated/aromatic product can be useful in theproduction of jet fuel, with minimal secondary processing beingrequired. In examples, secondary processing can include standardpetroleum-refining and processing methods. The amount of aromatichydrocarbon in the saturated/aromatic product can also be modulated byadjusting the temperature. It should be noted that various embodimentsoffer a direct and economical path for the production of liquidtransportation fuels, especially jet fuel, which require minimalsecondary processing.

IV. Optional Second Step Isomerization to Form Iso-Alkanes

In some embodiments, the first product is suitable for use as a fuel orfuel blendstock with little or no processing. In various embodiments,the first product can be subjected to optional further chemicallytransformative steps such as such as for example isomerization,selective cracking, or aromatization steps; e.g. in some embodimentsfurther chemical transformative steps are performed, while in otherembodiments further chemical transformative steps are not performed. Invarious embodiments of the present invention, the first product can besubjected to an optional isomerization step; e.g. in some embodiments anisomerization step is performed, while in other embodiments anisomerization step is not performed. In examples, any first productdescribed herein can be subjected to the isomerization step. Theisomerization step can be performed directly on the first product, orcan be performed on the first product after any suitable degree ofprocessing of the first product. In some embodiments the product thatresults from the isomerization (the second product) can be suitable foruse as a fuel or fuel blendstock with little or no processing, while inother embodiments the second product can be subjected to any suitabledegree of processing prior to being suitable for use as a fuel or fuelblendstock.

In some embodiments, performing optional reactive steps can produce asecond product that is more suitable as a fuel or blendstock than theproduct of the first step. In some examples, the product of the secondstep can be advantageously suited for easy use as a fuel or fuelblendstock with minimal or no further treatment needed. Advantageously,the second product can be better suited for use as a fuel or fuelblendstock than other methods, having hydrocarbon chain length ranges orproduct distributions better suited for fuel or fuel blendstock use thanthose produced by other methods, and being produced with lessconsumption of energy or valuable materials than other methods.

In some examples, the isomerization step can include a dewatering step.The dewatering step can include removal of water from the startingmaterial for the isomerization step. The dewatering step can include anysuitable procedure that removes a suitable amount of water from thehydrocarbon starting material. In some examples, the dewatering step caninclude cooling the hydrocarbon mixture to any suitable temperature, forexample the hydrocarbon mixture can be cooled to ambient temperature(e.g. 20° C.-30° C.). The dewatering step can include allowing the lesspolar hydrocarbon-containing phase to separate from a more polarwater-containing phase. The water-containing phase can then bephysically separated from the hydrocarbon-containing phase. In someexamples, the hydrocarbon can be placed in contact with molecularsieves, for instance 4-Å molecular sieves, which can further removewater. Generally, for larger amounts of water, a phase separation can beperformed first, then a second step contacting with molecular sieves.

In some examples, the isomerization step can include a deacidificationstep. The deacidification step can include removal of acid from thestarting material for the isomerization step. Any suitable method ofacid removal can be used for the deacidification step. In one example,removal of the water-containing phase during a dewatering step cansubstantially remove the acid, due to preference of the acid to residein the more polar water-containing phase, advantageously combiningdewatering with deacidification. In some examples, treatment of theunderwatered or dewatered hydrocarbons with a basic material can allowfor deacidification. In some embodiments, contacting the hydrocarbonswith molecular sieves can further deacidify the hydrocarbons, due tobasic properties of certain molecular sieves, advantageously combiningdewatering with deacidification.

The isomerization step includes isomerizing the hydrocarbon. Anysuitable proportion of the hydrocarbon can be isomerized in theisomerization step. For example, about 1 wt %, 5 wt %, 10 wt %, 20 wt %,30 wt %, 40 wt %, 50 wt %, 60 wt %, 70 wt %, 80 wt %, 90 wt % or about95 wt % of the hydrocarbon can be isomerized. The isomerization step caninclude contacting hydrocarbon with an isomerization catalyst. Forexample, the isomerization step can include passing a dried deacidifiedhydrocarbon over a bed of isomerization catalyst. In some examples,multiple contactings, or passes, can be performed to elicit a desiredproportion of isomerization of the hydrocarbon. In some example, eachcontacting or pass provides about 1 wt %, 5 wt %, 10 wt %, 20 wt %, 30wt %, 40 wt %, 50 wt %, or about 60 wt % isomerization of thehydrocarbon. Any suitable number of contacting or passes can beconducted, for example 1, 2, 3, 4, 5, 6, or 7 contactings or passes canbe conducted.

Any suitable isomerization catalyst can be used to effect theisomerization. For example, catalysts which possess a suitable balanceof catalytic metal dehydrogenation/hydrogenation activity and supportacidity can be used. Support acidity can be a controlling feature, alongwith operational temperature, which can determine the amount of carbonchain cracking that will occur. Strongly acidic supports can result ingreater amounts of chain cracking at a given temperature than a weaklyacidic support at the same temperature. Support acidity can becontrolled by the silica-alumina ratio in the support. Additionally, thesilica-alumina ratio in the support can control the pore size of thesupport. Pore size can also control cracking to a certain degree, againbased upon operational temperature. Isomerization catalysts with strongdehydrogenation/hydrogenation activity and weak support acidity may findgreater utility in the production of diesel fuel fractions.Isomerization catalysts with moderate acidity and strongdehydrogenation/hydrogenation activity may find greater utility in theproduction of jet fuel fractions. Isomerization catalysts with strongacidity may find greater utility in production of naphtha fractions.Suitable isomerization catalysts include any suitable isomerizationcatalyst known to one of skill in the art, such as those having two ormore catalytic metals and a silica-alumina support, wherein the metalsand support can be present in any suitable proportion.

Any suitable temperature can be used during the isomerization. Forexample, operation of an isomerization catalyst at a moderately lowtemperature, such as about 280° C.-about 380° C. or about 320° C.-about340° C., may find utility in the production of diesel fuel, especiallylow-cloud point diesel fuel. Operation of an isomerization catalyst atmoderate temperature may find utility in the production or jet fuel.Operation of an isomerization catalyst at high temperature, such asabout 320° C.-about 420° C. or about 360° C.-about 380° C., may findutility in the production of naphtha and gasoline-blendstock fuels.Suitable temperature ranges can include, for example, about 100° C.-500°C.

Any suitable pressure can be used during the isomerization. For example,operation of an isomerization catalyst at high hydrogen pressure, suchas about 600 psig-900 psig or about 700 psig-800 psig, may suppress thedehydrogenation activity of the catalyst, resulting in only slightisomerization, but potentially significant cracking. Operation of anisomerization catalyst at moderate hydrogen pressure, such as about 250psig-about 700 psig, may provide high isomerization with only slightcracking. Operation of an isomerization catalyst at low hydrogenpressure, such as about 150 psig-about 250 psig, may suppress thehydrogenation activity of the catalyst, resulting in significantcracking as well as alkene production. Suitable hydrogen pressures caninclude about 100 psig-about 900 psig.

Any suitable liquid flow rate can be used during the isomerization. Forexample, a liquid flow rate of about 0.1 to about 20 reactor volumes perhour or about 0.5-about 10 reactor volumes per hour can be a suitableflow rate.

In some embodiments the product that results from the isomerization (thesecond product) can be suitable for use as a fuel or fuel blendstockwith little or no processing, while in other embodiments the secondproduct can be subjected to any suitable degree of processing prior tobeing suitable for use as a fuel or fuel blendstock. The processing, ifperformed, can include any suitable processing. The processing caninclude distillation. In some examples, distillation of the isomerizedmixture can provide fuels or fuel blendstocks useful in spark ignitionor compression ignition engines. The blending of appropriate distillatefractions with appropriate petroleum-derived aromatic hydrocarbons andmixtures of aromatic hydrocarbons, can provide a renewable petroleumblend of hydrocarbons that complies with various jet fuelspecifications, such as for example a U.S. military specification forjet fuel, such as MIL-DTL-83133F.

V. Control Over the Proportion of Hydrocarbon Compounds Having anOdd-Number of Carbons, Hydrocarbon Compounds Having an Even-Number ofCarbons, and Cyclic Hydrocarbons

In various embodiments, during the hydrotreatment of the feedstock,variation of temperature, variation of the catalyst, or both, can causethe proportion of hydrocarbons in the product composition having anodd-number of carbon atoms in the product composition having aneven-number of carbon atoms to vary in a controllable fashion. Invarious embodiments, during the hydrotreatment of the feedstock,variation of temperature, variation of the catalyst, or both, can causethe proportion of hydrocarbons in the product composition that arecyclic versus hydrocarbons in the product composition that are acyclicto vary in a controllable fashion. By allowing control over theproportion of odd versus even carbon atom-containing hydrocarbons in theproduct, and cyclic versus acyclic hydrocarbons in the product, therange of hydrocarbon chain lengths can be more precisely controlled, andthe amount of cyclic hydrocarbons in the product can be more preciselycontrolled, advantageously allowing the production of fuels or fuelblendstocks with no or minimal processing with greater efficiency andless use of financial or energy resources than other methods. Suchcontrol can be effected when using any suitable feedstock as describedherein, including at least one of renewable TAGs, renewable FFAs, orrenewable C₁-C₅ FAEs.

Renewable TAGs have fatty acid portions that possess even numbers ofcarbons. The renewable TAG, renewable FFA, and renewable C₁-C₅ FAE ofthe feedstock of the present invention can have fatty acid portions thathave predominantly even numbers of carbon atoms, for example greaterthan about 60 mol %, 70 mol %, 80 mol %, 90 mol %, 95 mol %, 96 mol %,97 mol %, 98 mol %, 99 mol %, 99.5% mol % or about 100 mol % of thefatty acids portions have even numbers of carbon atoms. Duringhydrotreatment a combination of reactions can occur, as describedherein. Some of the reactions that can occur do not result in the lossof any carbon atoms, while other reactions result in the loss of carbonatoms. In some examples, the reactions that cause loss of carbon atomscan result in the loss of an odd number of carbon atoms, such as onecarbon atom. Likewise, some reactions result in cyclization, whileothers do not. Not intending to limit the method of the presentinvention to any mechanism or theory of operation, by varying thetemperature or catalyst used in the hydrotreatment, the rates of one ofmore of the reactions can be varied such that either reactions thatconserve carbon within the chain can predominate, or reactions thatoccur with release of carbon from the chain can predominate. Likewise,by varying the temperature or catalyst used in the hydrotreatment, therate of one or more of the reactions can be varied such that eitherreaction that do not result in the cyclization of compounds predominate,or reactions that do result in the cyclization of compound predominate.By controlling which types of reactions predominate, the distributionwithin the product mixture of hydrocarbons with an odd-number of carbonatoms versus hydrocarbons with an even-number of carbon atoms can becontrolled, and likewise the amount of cyclic hydrocarbons in theproduct mixture can be controlled.

The Effect of Temperature on the Variation of Products

When operating a hydrotreatment process for the conversion of feedstockto hydrocarbons, a number of reactions occurring simultaneously can giverise to the observed products. Heat is generated or consumed by thevarious reactions that occur. Each particular chemical reaction has itsown enthalpy of reaction. Additionally, in some examples, the rate ofsome reactions may be someone dependant on the rates of other reactions.For example, since some reactions can share a particular startingmaterial and scarcity of that material due to a high rate of onereaction can starve the other reaction. In another example, the productof one reaction can act as starting material for another reaction, suchthat if one reaction generates large amounts of starting material foranother reaction, the other reaction can occur at a higher rate. Theobserved overall heat of reaction is a mathematical sum of individualenthalpies based upon the extent of which each reaction contributes tothe products produced.

Some examples of models of the various reactions that can occur duringhydrotreatment are shown in Table 1. The reactions shown in Table 1focus on the conversion of one particular example species that may ormay not be in an actual feedstock in an embodiment of the presentinvention to one particular example product species that may or may notbe in an actual first product mixture in an embodiment of the presentinvention. The reactions are selected to show the approximate averageenthalpy contribution from each of several different types of reactionsthat can occur during hydrotreatment. The enthalpies given in Table 1are non-limiting, and embodiments of the present invention may havereactions with enthalpies different than or similar to the enthalpiesshown in Table 1. The enthalpies shown in Table 1 are the calculatedenthalpy of reaction at 350° C. and are approximate.

TABLE 1 Individual Reactions and Associated Enthalpies at 350° C.Reaction Enthalpy @ 350° C. Carboxylate Reduction: C₁₈H₃₆O₂(ODA) +3H₂(g) = C₁₈H₃₈ + 2H₂O −39.094 kcal/mole Carboxylate Decarbonylation:C₁₈H₃₆O₂(ODA) + H₂(g) = C₁₇H₃₆(HDA) + 14.782 kcal/mole CO(g) + H₂O(g)Carboxylate Decarboxylation: C₁₈H₃₆O₂(ODA) = C₁₇H₃₆(HDA) + CO₂(g) 5.522kcal/mole Alkene Reduction: C₁₈H₃₄(1ODYg) + 2H₂(g) = C₁₈H₃₈(ODA) −51.002kcal/mole C-C Bond Cracking: C₁₇H₃₆(HDAl) + H₂(g) = C₁₅H₃₂(PDAl) +C₂H₆(g) −9.259 kcal/mole Glycerine Production to Propane: C₃H₈O₃(GLYl) +3H₂(g) = C₃H₈(PPEg) + −47.118 kcal/mole 3H₂O(g) Aromatic CompoundFormation: C₁₆H₃₄(HDAl) = C₁₆H₂₆(DCBg) + 81.307 kcal/mole 4H₂(g)

In Table 1, C₁₈H₃₆O₂(ODA) indicates octadecanoic acid, C₁₇H₃₆(HDA)indicates heptadecane, C₁₈H₃₄(1ODYg) indicates octadecadiene,C₁₇H₃₆(HDA1) indicates heptadecane, C₁₅H₃₂(PDA1) indicates pentadecane,C₃H₈O₃(GLY1) indicates glycerine, C₃H₈(PPEg) indicates propane, C₁₆H₂₆(DCBg) indicates decylbenzene.

Reactions associated with negative enthalpies are reactions that releaseheat as they occur, while those with positive enthalpies are reactionsthat consume heat as they occur. Therefore, in Table 1, the greatestheat releasing reaction on a molar basis is the alkene reductionreaction, and the greatest heat consuming reaction is aromatic compoundformation reaction.

The enthalpies of the hydrotreatment reactions can change as a result ofchanges in temperature. The result can be that some reactions cangenerate more or less heat as the temperature of the reaction systemincreases, while other reactions can absorb more or less heat as thetemperature of the reaction system increases. Some reactions may notchange significantly as the temperature of the reaction system changes.FIG. 1 illustrates the calculated changes in enthalpy for the variousreactions shown in Table 1 for the temperate range of 300° C. to 500° C.The amount of change shown is based upon the reaction enthalpy at 300°C. (e.g. at T=300° C., change is zero).

In the model, the rates of each of the reactions shown in Table 1 canaffect one another based competition between the reactions for variousstarting materials or physical locations, for example for hydrogenmolecules or discrete catalytic sites, if either or both are required.The rate of each reaction determine to what extent each reactioncontributes to the products formed in the process. Similarly toenthalpies, the relative rates can increase or decrease relative to oneanother with changes in reaction system temperature. This can mean thatas a heat releasing reaction increases the temperature of the reactionmixture, other reactions can in some examples increase in relative rateto either release more or less heat or consume more or less heat,thereby either increasing the temperature of the reaction mixture viaexothermic processes, or decreasing the temperature of the reactionmixture via endothermic processes.

In certain embodiments of the present invention, with the use of ahigher temperature during hydrotreatment, while keeping hydrogen feedrate constant and feedstock feed rate constant, the proportion ofhydrocarbons having an odd-number of carbon atoms and hydrocarbons thatare aromatic products increases relative to hydrocarbons having aneven-number of carbon atoms. Embodiments can have any suitable variationin hydrogen feed rate and feedstock feed rate; but they can be heldconstant to aid in understanding perturbation of reaction kinetics viatemperature or catalyst variation. Not intending to limit the method toany mechanism or theory of operation, as the temperature increasesduring hydrotreatment, the rate of hydrogen consumption can increase forthe reactions involving reduction of the carboxyl group and reduction ofcarbon-carbon double bonds. The increase in hydrogen consumption ratecan lead to scarcities of hydrogen in the vicinity of catalytic sites.With a shortage of hydrogen, reactions which require less hydrogen, orin some examples reactions that actually produce hydrogen, can becomerelatively favored over the reactions that consume hydrogen. The resultcan be an increase in relative rates of the less hydrogen consumptivereactions due to reaction system demands for hydrogen. If the particularless hydrogen consumptive reactions that occur in a greater proportionas the temperature increases are reactions that remove odd numbers ofcarbon atoms from the starting material, then in the product compositionhydrocarbons having an odd number of carbon atoms begin to increase inproportion compared to the amount of hydrocarbons having an even numberof carbon atoms. When the temperature decreases and hydrogen becomesmore plentiful due to decreasing reaction rates of hydrogen consumptivereactions, if the hydrogen consumptive reactions are reactions thatdon't remove carbon atoms or that remove even numbers of carbon atoms,then the proportion of hydrocarbons in the product mixture that haveeven numbers of carbon atoms will increase compared to the amount ofhydrocarbons have an odd number of carbon atoms.

Advantageously, as the temperature increases, the increase in the lesshydrogen consumptive processes can result in an overall lower heatgenerated by the reaction system as compared to the heat that would begenerated by the more highly hydrogen consumptive processes. Thereforeas the temperature of the reaction system increases, reactions whichproduce less heat, or consume heat occur at faster relative rates thanthey did at lower temperatures, thereby limiting the heat produced bythe reaction system. This series of phenomena can lead to aself-regulating temperature effect in the reaction system, beneficiallylimiting the propensity of the reaction system to suffer from anexothermic run-away reaction. This can be a significant benefit to thepresent method employing a nonsulfided catalyst.

Part II: Catalytic Factors

In some examples, by varying the catalyst used during the hydrotreatingstep, the proportion of hydrocarbons having odd versus even numbers ofcarbon atoms can be varied, and the overall amount of cyclichydrocarbons produced can be varied.

For example, catalyst can be used that has variations in the proportionof nickel or molybdenum. Any suitable variation can be used. Thepercentages given in this paragraph are weight percents based on thetotal weight of nickel and molybdenum and exclusive of any binder orsupport of any other component of the catalyst. For example, thecatalyst can be 100% nickel or 100% molybdenum. In some examples, thecatalyst can be about 1% nickel with the remainder molybnenum, or about2% nickel, or 3%, 4%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%,95%, 96%, 97%, 98%, or about 99% nickel with the remainder molybdenum.

Use of a catalyst that is entirely molybdenum or that has someproportion of molybdenum can result in formation of iso-paraffins aswell as normal-paraffins, and can result in formation of paraffinsresulting from cracking processes.

Use of a catalyst that is entirely nickel or that has some proportion ofnickel can result in less formation of iso-paraffins, and less formationof products arising from cracking processes, as compared to the use of amolybdenum catalyst. However, use of a nickel-containing catalyst canresult in a tendency toward production of odd-carbon chain hydrocarbons,arising from for example decarbonylation or decarboxylation reactions,versus the molybdenum-only catalyst. As discussed herein, a greatertendency toward decarbonylation or decarboxylation can lead to asignificant difference in the heat generated during a hydrotreatmentreaction. Additionally, lower temperatures can advantageously lead toless hydrogen consumption. The use of a nickel-only, predominantlynickel, or nickel containing catalyst can allow the use of a reactordesign that can use less heat management precautions as compared to ahydrotreatment reactor used with a catalyst having less nickel such as anickel-molybdenum catalyst with predominantly molybdenum, or amolybdenum-only catalyst. Due to potentially less hydrogen consumption,the use of a nickel-only catalyst, predominantly nickel catalyst, ornickel-containing catalyst can lead to reduced hydrogen consumption. Asa result, a stand-alone renewable fuel refinery using a nickel-onlycatalyst, predominantly nickel catalyst, or nickel-containing catalystcan in some embodiments require less hydrogen generation capacity than arefinery designed for use of a nickel-molybdenum, predominantlymolybdenum, or molybdenum-only catalyst.

VI. Examples Examples 1-9 Coconut Oil

The apparatus of Examples 1-9 was a continuous-flow reactor including apump system, gas flow system, high-pressure reactor vessel, reactorheater and temperature regulation device, product collection receptacle,and pressure regulation device. Appropriate instrumentation andelectronics were attached to the device to enable control and recordingof experimental conditions. Samples of product were removed through thesample receptacle and analyzed with appropriate analyticalinstrumentation (e.g., gas chromatography-mass spectrometry, GC-MS).Hydrogen was supplied to the reactor system from purchased cylinders.Feedstock material was supplied to the reactor system via ahigh-pressure pumping system. In Examples 1-9, 1.12 kg of a nonsulfidednickel-molybdenum hydrotreating catalyst (Criterion CR-424) was chargedto the reactor chamber. The chamber possessed a length-to-diameter ratioof 6. The catalyst was activated by warming to greater than 300° C.while a flow of hydrogen gas was passed over the catalyst. The moisturecontent of the exiting gas was measured. The activation was judgedcomplete approximately when the water content of the exiting gasdecreased.

Example 1

Coconut oil was supplied to the reactor at a rate of about 1 pound/hour.Hydrogen was supplied at a rate of about 20 standard cubic feet per hour(scfh). The reactor was maintained at about 340° C. The hydrogenpressure was regulated to about 80 psi. The temperature and flowconditions were maintained for about 3 hours once steady-stateconditions were achieved. The product was collected and analyzed.Results are shown in Table 2.

TABLE 2 Results from First Test Matrix Saturated Olefinic Fatty OilFlow, Temp., Pressure, H₂ Flow, Hydrocarbons, Hydrocarbons, Acids,Example lb/hr ° C. psig scfh % % % 1 1 340 80 20 43.8 27.4 19.0 2 1 350100 20 27.2 33.9 26.9 3 2 350 100 40 21.8 26.1 40.0 4 1 350 200 20 50.418.0 16.0 5 2 350 200 40 27.3 20.0 41.9 6 1 400 100 20 40.6 37.0 7.4 7 2400 100 40 37.7 32.3 16.9 8 1 400 200 20 73.5 10.5 3.2 9 2 400 200 5063.3 13.8 2.2

Example 2

Coconut oil was supplied to the reactor at a rate of about 1 pound/hour.Hydrogen was supplied at a rate of about 20 scfh. The reactor wasmaintained at about 350° C. The hydrogen pressure was regulated to about100 psi. The temperature and flow conditions were maintained for about 3hours once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 2.

Example 3

Coconut oil was supplied to the reactor at a rate of about 2pounds/hour. Hydrogen was supplied at a rate of about 40 scfh. Thereactor was maintained at about 350° C. The hydrogen pressure wasregulated to about 100 psi. The temperature and flow conditions weremaintained for about 3 hours once steady-state conditions were achieved.The product was collected and analyzed. Results are shown in Table 2.

Example 4

Coconut oil was supplied to the reactor at a rate of about 1 pound/hour.Hydrogen was supplied at a rate of about 20 scfh. The reactor wasmaintained at about 350° C. The hydrogen pressure was regulated to about200 psi. The temperature and flow conditions were maintained for about 3hours once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 2.

Example 5

Coconut oil was supplied to the reactor at a rate of about 2pounds/hour. Hydrogen was supplied at a rate of about 40 scfh. Thereactor was maintained at about 350° C. The hydrogen pressure wasregulated to about 200 psi. The temperature and flow conditions weremaintained for about 3 hours once steady-state conditions were achieved.The product was collected and analyzed. Results are shown in Table 2.

Example 6

Coconut oil was supplied to the reactor at a rate of about 1 pound/hour.Hydrogen was supplied at a rate of about 20 scfh. The reactor wasmaintained at about 400° C. The hydrogen pressure was regulated to about100 psi. The temperature and flow conditions were maintained for about 3hours once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 2.

Example 7

Coconut oil was supplied to the reactor at a rate of about 2pounds/hour. Hydrogen was supplied at a rate of about 40 scfh. Thereactor was maintained at about 400° C. The hydrogen pressure wasregulated to about 100 psi. The temperature and flow conditions weremaintained for about 3 hours once steady-state conditions were achieved.The product was collected and analyzed. Results are shown in Table 2.

Example 8

Coconut oil was supplied to the reactor at a rate of about 1 pound/hour.Hydrogen was supplied at a rate of about 20 scfh. The reactor wasmaintained at about 400° C. The hydrogen pressure was regulated to about200 psi. The temperature and flow conditions were maintained for about 3hours once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 2.

Example 9

Canola oil was supplied to the reactor at a rate of about 1 pound/hour.Hydrogen was supplied at a rate of about 50 scfh. The reactor wasmaintained at about 400° C. The hydrogen pressure was regulated to about200 psi. The temperature and flow conditions were maintained for about 3hours once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 2.

Examples 10-17 Yellow Grease

For Examples 10-17, a smaller reactor system was utilized. The reactortube possessed a length-to-diameter ratio of about 40. The tube wasloaded with a total of about 70 grams of catalyst for the experimentslisted below. The feedstock for Examples 10-17 was yellow greaseobtained from a french fry factory and included predominantly TAGs. Theyellow grease possessed a significant (about 2.6%) FFA content.

Example 10

Yellow grease was supplied to the reactor at a rate of about 1milliliter/minute (mL/min). Hydrogen was supplied at a rate of about1064 standard cubic centimeters/minute (sccm). The reactor wasmaintained at about 474° C. The hydrogen pressure was regulated to about750 psi. The temperature and flow conditions were maintained for about30 minutes once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 3.

TABLE 3 Results from Yellow Grease as Feedstock Saturated AromaticOlefinic Oil Flow, Temp., Pressure, H₂ Flow, Hydrocarbons, Hydrocarbons,Hydrocarbons, Example mL/min ° C. psig sccm % % % 10 1.0 474 750 1064 909 0 11 1.0 480 750 1050 77 17 3 12 1.0 490 750 1050 64 32 1 13 1.0 502750 1050 56 39 2 14 1.0 530 750 1050 37 60 1 15 1.5 498 750 1050 91 7 216 4.5 482 750 1066 63 7 21 17 4.5 487 750 1088 62 13 23

A mixture of reactions, including for example hydrodeoxygenation,decarboxylation, and decarbonylation reactions, can occur simultaneouslyduring the conversion of feedstock to hydrocarbon product. Thehydrodeoxygenation reactions can provide a hydrocarbon productpossessing even-numbered carbon chains, such as octadecane. Thedecarboxylation and decarbonylation reactions provide a hydrocarbonproduct possessing odd-numbered carbon chains such as heptadecane. Theratio of C17 to C18 product observed was about 0.79 to 1. Coincidentcracking reactions provide a mixture of lower normal hydrocarbons. Theobserved ratios of even- and odd-numbered hydrocarbon chains weremeasured as C15:C16=0.57, C13:C14=1.22, C11:C12=1.15, C9:C10=1.11, andC7:C8=1.03.

The simultaneous production of both even and odd carbon chains ofvarying lengths can facilitate the ultimate production of a finalproduct including a petroleum-like fuel or fuel blendstock.

Example 11

Yellow grease was supplied to the reactor at a rate of about 1 mL/min.Hydrogen was supplied at a rate of about 1050 sccm. The reactor wasmaintained at 480° e. The hydrogen pressure was regulated to about 750psi. The temperature and flow conditions were maintained for 30 minutesonce steady-state conditions were achieved. The product was collectedand analyzed. Results are shown in Table 3.

Example 12

Yellow grease was supplied to the reactor at a rate of about 1 mL/min.Hydrogen was supplied at a rate of about 1050 sccm. The reactor wasmaintained at about 490° C. The hydrogen pressure was regulated to about750 psi. The temperature and flow conditions were maintained for about30 minutes once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 3.

Example 13

Yellow grease was supplied to the reactor at a rate of 1 mL/min.Hydrogen was supplied at a rate of about 1050 sccm. The reactor wasmaintained at about 502° C. The hydrogen pressure was regulated to about750 psi. The temperature and flow conditions were maintained for about30 minutes once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 3.

Example 14

Yellow grease was supplied to the reactor at a rate of about 1 mL/min.Hydrogen was supplied at a rate of about 1050 sccm. The reactor wasmaintained at 530° C. The hydrogen pressure was regulated to about 750psi. The temperature and flow conditions were maintained for about 30minutes once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 3.

Example 15

Yellow grease was supplied to the reactor at a rate of about 1.5 mL/min.Hydrogen was supplied at a rate of about 1050 sccm. The reactor wasmaintained at 498° C. The hydrogen pressure was regulated to about 750psi. The temperature and flow conditions were maintained for about 30minutes once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 3.

Example 16

Yellow grease was supplied to the reactor at a rate of about 4.5 mL/min.Hydrogen was supplied at a rate of about 1066 sccm. The reactor wasmaintained at about 482° C. The hydrogen pressure was regulated to about750 psi. The temperature and flow conditions were maintained for about30 minutes once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 3.

Example 17

Yellow grease was supplied to the reactor at a rate of about 4.5 mL/min.Hydrogen was supplied at a rate of about 1088 sccm. The reactor wasmaintained at 487° C. The hydrogen pressure was regulated to about 750psi. The temperature and flow conditions were maintained for about 30minutes once steady-state conditions were achieved. The product wascollected and analyzed. Results are shown in Table 3.

Example 18 Product Fuels

Hydrocarbon product obtained from process conditions such as thosedescribed in Tables 2 and 3 was subjected to petroleum-refiningoperations, including isomerization, aromatization, hydrogenation, anddistillation under conditions known to those skilled in the art, suchthat a fuel was produced that complied with the military specificationfor JP-8 (MIL-DTL-83133E). The fuel possessed a flash point of 49° C., afreeze point of −52° C., and an energy density of 42.9 MJ/kg.Furthermore, the fuel complied with all aspects of MIL-DTL-83133E,including physical density, distillation (D-86), etc.

The processing of TAG, either virgin or waste, according to the examplesabove, provides a fuel possessing properties consistent with drop-incompatibility and fit-for-purpose usage for a variety of fuels, forexample according to MIL-DTL-83133E or MIL-OTL-83133F.

Examples 19-21 Feedstock Predominantly Fatty Acids

The reactor system used for Examples 19-21 possessed a tubular reactorwith internal dimensions of 1.5-inch diameter and 56-inch length. Thefeedstock was fatty acid from a biodiesel plant, which was removed fromTAGs via a stripper column. The reactor was heated to the desiredoperating temperature by means of heating elements affixed to theoutside of the reactor tube. Liquid was supplied to the reactor by meansof a high-pressure pump that drew fatty acid in a liquid state from aheated reservoir. The fatty acid was passed through a tubular preheaterprior to introduction to the tubular reactor. Hydrogen was supplied fromhigh-pressure cylinders, with the flow rate controlled by means of amass flow controller. The pressure of the reactor system was controlledby means of a back-pressure controller located at the end of the reactorsystem. The end of the reactor system possessed a chiller and a pressureletdown system to aid in sample collection. Temperatures, pressures, andflow rates were controlled via PC-driven proportional integralderivative (PID) process control software (e.g. the computer analyzedchanges in temperate, derived a rate of change, then adjusted electricalpower to the heating elements in proportion to the required change thatmaintained a relatively constant temperature).

Example 19

The reactor was charged with a nonsulfided hydrotreating catalyst (about1.5 kg). The catalyst bed was slowly warmed to the desired operatingtemperature while passing a steady flow of hydrogen over the catalystbed. A hydrogen flow of about 50 standard cubic feet per hour (scfh),liquid flow of about 2 liters per hour (lph) of fatty acid, and areactor pressure of about 735 pounds per square inch (psi) wereestablished. The temperature of the reactor was stabilized at about 430°C. Fatty acids as described by Sample 1 in Table 4 were pumped throughthe reactor, with product being formed consistent with the compositiondescribed in Table 5.

TABLE 4 Compositions of Fatty Acid Mixtures Converted to HydrocarbonsSample 1, % Sample 2, % Fatty Acid composition composition C16:0 10.421.0 C16:1 — 10.3 C18:0 3.6 6.9 C18:1 25.3 39.9 C18:2 54.8 19.0 C18:35.1 — C20:0 0.7 0.1 C20:1 — 0.5 Others 0.1 0.3

TABLE 5 Hydrocarbon Distribution from Processing of Soy Fatty AcidCarbon Number % n-Paraffin % i-Paraffin % c-Paraffin % Olefin 18 35.758.2 — 1.89 17 10.34 2.4 — 1.04 16 14.28 0.83 — — 15 3.95 0.36 — — 141.56 0.14 0.02 — 13 1.23 0.22 — — 12 1.26 0.26 — 0.08 11 1.18 0.26 — —10 1.20 0.24 0.02 0.08 9 1.05 0.23 0.04 — 8 1.16 0.31 0.07 — 7 1.15 1.040.18 — 6 0.97 0.24 0.27 0.06 5 0.67 0.09 0.15 — 4 0.31 — — — 3 0.07 — —— Totals 76.13 14.82 0.75 3.15

The recovered mass yield of liquid products was 95.8%. Analysisindicated that about 85.0 wt % of the fatty acid had been converted tohydrocarbon and about 10.8 wt % was converted to water, with theremainder converted to other gaseous products. Analysis of the crudeproduct mixture for fatty acids was performed. Trace amounts of fattyacid were detectable by sensitive analytical methods. The amount offatty acid present in the hydrocarbon phase was determined by anacid-base titration, with the results expressed as mg of potassiumhydroxide (KOH) consumed per gram of hydrocarbon. This test providedresults of less than 0.20 milligram KOH per gram of hydrocarbon.

The processing of B99 biodiesel, which includes C₁-C₅ FAEs, producedsimilar results.

Example 20

The reactor was charged with a nonsulfided hydrotreating catalyst (about1.5 kg). The catalyst bed was slowly warmed to the desired operatingtemperature while passing a steady flow of hydrogen over the catalystbed. A hydrogen flow of about 50 scfh, a liquid flow of about 2 lph offatty acid, and a reactor pressure of about 530 psi were established.The reactor temperature was stabilized at about 430° C. Fatty acid asdescribed by Sample 2 in Table 4 was pumped through the reactor, withproduct being formed consistent with the composition described in Table5. The recovered mass yield was about 97.1%. Analysis of the dataindicated that about 86.8 wt % of the fatty acid had been converted tohydrocarbons and about 10.3 wt % converted to water, with the balancebeing converted to gaseous products.

Example 21

The reactor was charged with a catalyst possessing hydrocarbonisomerization activity. The catalyst was activated by slowly warming thecatalyst to the desired operating temperature while passing a steadyflow of hydrogen over the catalyst. The reactor was pressurized to thedesired operating pressure, and the desired hydrogen flow rate wasestablished. A flow of dewatered and deacidified product described inTable 5 was introduced to the reactor at an appropriate flow rate. Ifrequired, multiple passes through the isomerization catalyst bed wereutilized to obtain a degree of isomerization suitable for the particularfuel product being sought. The product mixture resulting from thedewatering, deacidification, and isomerization steps is illustrated inTable 6.

TABLE 6 Distribution of Products from Dewatering, Deacidification, andIsomerization Steps Carbon Number % n-Paraffin % i-Paraffin % c-Paraffin% Olefin 18 0.22 4.09 — — 17 1.06 10.91 — — 16 3.25 8.10 — — 15 1.744.68 — — 14 1.05 2.86 — — 13 1.24 5.44 — — 12 1.40 6.08 — — 11 1.53 5.770.29 — 10 1.67 6.29 0.46 — 9 1.72 6.03 0.85 — 8 2.02 4.33 0.94 — 7 1.953.45 1.25 — 6 1.55 2.42 0.54 — 5 — 2.25 — — 4 — 0.59 — — 3 — — — —Totals 20.40 73.29 4.33 —

A portion of isomerized product possessing between about 70% and 80%isomerization was subjected to distillation. A distillate cut wasproduced that displayed a flash point of 43° C. and a freeze point of−49° C. A fuel with such properties can be useful as a syntheticparaffinic kerosene (SPK) jet fuel. Additionally, blending such an SPKwith appropriate petroleum-derived or coal derived aromatic compoundscan provide a fuel possessing, for example, a flash point of 44° C., afreeze point of −59° C., and a physical density of 0.789 kilograms perliter. A fuel with such properties can be useful as JP-8, a jet fuelthat complies with all fuel property requirements described in U.S.Military Fuel Specification MIL-DTL-83133F.

Example 22 Temperature Control of Proportion of Hydrocarbons Having EvenNumbers of Carbon Atoms Versus Odd Numbers of Carbon Atoms and CyclicHydrocarbons

Utilizing data from examples 10, 14, 16, and 17, an estimate of theenthalpy of reaction was calculated for each example, using the modelequations given in Table 1. A spreadsheet utilizing enthalpiescalculated in 10° C. increments between 300° C. and 530° C. was used tothe overall enthalpies of reaction. Enthalpy data was subjected to aweighted-averaging for temperatures that did not fall directly on anincrement. The numerical enthalpies resulting from the calculations areshown in Table 7.

TABLE 7 Calculated Estimated Enthalpies for Examples 10, 14, 16, and 17.Calculated Enthalpy Example Reaction Temperature (° C.) (kcal/mole) 10474 −178.817 14 482 −147.176 16 487 −143.832 17 530 −50.752

Graphically, the results are presented in FIG. 2, which illustratescalculated enthalpy versus temperature.

In Examples such as Examples 10, 14, 16, and 17, it was observed that astemperature increased the proportion of C₁₈ product decreases, while theproportion of C₁₇ product increased. Additionally, as temperatureincreases, the amount of aromatic product formed also increased. Thetrend data extracted from gas chromatograms is shown in Table 8. The useof the nonsulfided catalyst allows higher temperatures, which as shownherein can cause the formation of larger proportions of cyclichydrocarbons (e.g. see “aromatics” in Table 8), which can advantageouslyallow the more efficient production of fuels and fuel blendstockssuitable as jet fuels.

TABLE 8 Extracted Data from Gas Chromatography Example Temperature (°C.) % C₁₇ % C₁₈ % Aromatics 10 474 38.6 61.4 9.2 14 530 100 0 60 16 48263 37 7.4 17 487 62 38 12.6

Example 23 Catalyst Control of Product Distribution

To determine the relative value of the individual catalytic metalspresent in a nickel-molybdenum hydrotreating catalyst, custom preparedcatalysts were acquired that were identical to a commercialnickel-molybdenum hydrotreating catalyst except that one samplecontained only nickel, and the second sample contained only molybdenum.A summary of results obtained from these catalysts are shown in Table 9.The calculations were conducted for a temperature of 350° C. The systemwas operated in a bottom-up flow configuration at 1000 psig, 0.75-1.0mL/min canola oil, 1000 sccm H², and 370° C. at the top of the bed.

TABLE 9 Results obtained from Ni-only or Mo-only Catalysts n-C₁₇ (arean-C₁₈ (area Calculated Catalyst percent) percent) Enthalpy (kcal/mole)Molybdenum- 9.02 41.95 −212.7 only Nickel-only 69.63 18.70 −128.6

The data shown in Table 9 shows only 50.97% closure (e.g. only 50.97% ofmaterials were accounted for in n-C¹⁷ and n-C¹⁸ areas) for themolybdenum-only catalyst, but 88.33% closure for the nickel-onlycatalyst. This is likely due to the fact that use the molybdenum-onlycatalyst resulted in significant formation of iso-paraffins as well asnormal-paraffins, as well as paraffins resulting from crackingprocesses, evidenced including by the gas chromatogram generated by thesamples. In contrast, the nickel-only catalyst showed virtually noformation of iso-paraffins, and little formation of products arisingfrom cracking processes. However, the nickel-only catalyst showed agreater tendency to produce odd-carbon chain products, arising from forexample decarbonylation or decarboxylation reactions, versus themolybdenum-only catalyst. A greater tendency toward decarbonylation ordecarboxylation can lead to a significant difference in the heatgenerated during a hydrotreatment reaction. The nickel-only catalyst iscalculated to provide a much lower enthalpy of reaction, therebypotentially leading to a reactor design that does not require asextensive heat management hardware as would a nickel-molybdenum reactordesign, or a molybdenum-only design. Additionally, the use of anickel-only catalyst would lead to greatly reduced hydrogen consumption.Therefore a stand-alone renewable fuel refinery would require lesshydrogen generation capacity than a refinery designed for use of anickel-molybdenum or molybdenum-only catalyst.

While various embodiments of the invention have been shown anddescribed, modifications thereof can be made by one skilled in the artwithout departing from the spirit and teachings of the disclosure. Theembodiments described herein are exemplary only and are not intended tobe limiting. Many variations and modifications of the inventiondisclosed herein are possible and are within the scope of the invention.Where numerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g., from about 1 to about 10 includes 2, 3, 4,etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). Use of theterm “optionally” with respect to any element of a claim is intended tomean that the subject element is required or, alternatively, is notrequired. Both alternatives are intended to be within the scope of theclaim. Use of broader terms such as comprises, includes, having, etc.,should be understood to provide support for narrower terms such asconsisting of, consisting essentially of, comprised substantially of,etc.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedcan include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

Accordingly, the scope of protection is not limited by the descriptionset out above but is only limited by the claims that follow, that scopeincluding all equivalents of the subject matter of the claims. Each andevery claim is incorporated into the specification as an embodiment ofthe present invention. Thus the claims are a further description and arean addition to the preferred embodiments of the present invention. Thediscussion of a reference is not an admission that it is prior art tothe present invention.

In this document, the terms “a,” “an,” or “the” are used to include oneor more than one unless the context clearly dictates otherwise. The term“or” is used to refer to a nonexclusive “or” unless otherwise indicated.In addition, it is to be understood that the phraseology or terminologyemployed herein, and not otherwise defined, is for the purpose ofdescription only and not of limitation. Any use of section headings isintended to aid reading of the document and is not to be interpreted aslimiting; information that is relevant to a section heading may occurwithin or outside of that particular section. The disclosures of allpatents, patent applications, and publications cited herein are herebyincorporated by reference, to the extent they provide exemplary,procedural, or other details supplementary to those set forth herein.

Additional Embodiments

The present invention provides for the following exemplary embodiments,the numbering of which is not to be construed as designating levels ofimportance:

Embodiment 1 provides a method of producing a hydrocarbon product, themethod including: hydrotreating a feedstock including at least one of arenewable triacylglyceride (TAG), renewable fatty acid, renewable fattyacid C₁-C₅ alkyl ester (C₁-C₅ FAE), or a mixture thereof, in thepresence of a nonsulfided hydrotreating catalyst, to produce a firstproduct including hydrocarbons; wherein the renewable TAG, renewableFFA, and renewable C₁-C₅ FAE include fatty acid units that have an evennumber of carbon atoms; wherein in the first product, a proportion ofhydrocarbons with an odd-number of carbon atoms, cyclic hydrocarbons, orhydrocarbons with an even-number of carbon atoms is dependent on anaverage temperature used during the hydrotreating.

Embodiment 2 provides the method of Embodiment 1, wherein greater than90 mol % of the fatty acid groups in the renewable TAG, renewable FFA,and renewable C₁-C₅ FAE have an even number of carbon atoms.

Embodiment 3 the method of any one of Embodiments 1-2, further includingcontrolling the average temperature during hydrotreating to be a higheraverage temperature, such that in the first product the ratio ofhydrocarbons having an odd-number of carbon atoms to hydrocarbons havingan even-number of carbon atoms is higher, or the ratio of cyclichydrocarbons to hydrocarbons having an even-number of carbon atoms ishigher, as compared to a corresponding ratio obtained wherein theaverage temperature used during hydrotreating is controlled to be alower average temperature.

Embodiment 4 provides the method of any one of Embodiments 1-3, furtherincluding controlling the average temperature during hydrotreating to bea lower average temperature, such that in the first product the ratio ofhydrocarbons having an odd-number of carbon atoms to hydrocarbons havingan even-number of carbon atoms is lower, or the ratio of cyclichydrocarbons to hydrocarbons having an even-number of carbon atoms islower, as compared to a corresponding ratio obtained wherein the averagetemperature used during hydrotreating is controlled to be a higheraverage temperature.

Embodiment 5 provides the method of any one of Embodiments 1-4 whereinthe nonsulfided hydrotreating catalyst includes at least one metalselected from Groups 6, 8, 9, and 10 of the periodic table.

Embodiment 6 provides the method of any one of Embodiments 1-5, whereinthe hydrotreating catalyst includes molybdenum (Mo).

Embodiment 7 provides the method of any one of Embodiments 1-6, whereinin the first product, a proportion of at least one of paraffinsresulting from cracking processes or iso-paraffins is greater ascompared to a corresponding proportion of at least one of paraffinsresulting from cracking processes or iso-paraffins obtained when thehydrotreating catalyst has less or no molybdenum.

Embodiment 8 provides the method of any one of Embodiments 5-7 whereinthe hydrotreating catalyst includes nickel (Ni).

Embodiment 9 provides the method of Embodiment 8, wherein in the firstproduct, a proportion of hydrocarbons having an odd number of carbonatoms is greater as compared to a proportion of hydrocarbons having anodd number of carbon atoms when the hydrotreating catalyst has less orno nickel.

Embodiment 10 provides the method of any one of Embodiments 5-9 whereinthe hydrotreating catalyst includes at least one metal selected from thegroup consisting of palladium (Pd), platinum (Pt), nickel (Ni), andcombinations thereof.

Embodiment 11 provides the method of any one of Embodiments 5-10 whereinthe hydrotreating catalyst includes nickel and molybdenum or cobalt andmolybdenum.

Embodiment 12 provides the method of any one of Embodiments 5-11 whereinthe hydrotreating catalyst further includes a support selected fromalumina, silica, and combinations thereof.

Embodiment 13 provides the method of any one of Embodiments 1-12 whereinthe TAG in the feedstock is derived from at least one of plants,animals, algae, other microorganisms, or combinations thereof.

Embodiment 14 provides the method of any one of Embodiments 1-13 whereinthe renewable fatty acid in the feedstock is derived from hydrolysis ofa renewable TAG.

Embodiment 15 provides the method of any one of Embodiments 1-14 whereinthe renewable C₁-C₅ FAE in the feedstock is derived from a renewableTAG.

Embodiment 16 provides the method of any one of Embodiments 1-15 whereinhydrotreating is performed at a temperature in the range of about 340°to about 400° C. and a pressure in the range of about 500 psig to about750 psig.

Embodiment 17 provides the method of Embodiment 16 further includingsubjecting the first product to at least one process selected fromisomerization, cracking, and aromatization to produce a second productsuitable for use as gasoline, naptha, kerosene, jet fuels, or dieselfuels.

Embodiment 18 provides the method of any one of Embodiments 1-17 whereinhydrotreating is performed at a temperature in the range of about 470°to about 530° C. and a pressure in the range of about 750 psig to about1000 psig.

Embodiment 19 provides the method of Embodiment 18 wherein the firstproduct includes greater than 50 wt % saturated and aromatichydrocarbons.

Embodiment 20 provides a method of producing a transportation fuel, themethod including: hydrotreating a feedstock including at least one of arenewable triacylglyceride (TAG), renewable fatty acid, renewable fattyacid C₁-C₅ alkyl ester (C₁-C₅ FAE), or a mixture thereof, in thepresence of a nonsulfided hydrotreating catalyst, to produce a firstproduct including hydrocarbons; and subjecting the first product to atleast one process selected from aromatization, cracking, andisomerization, to produce a second hydrocarbon product selected fromgasoline, naptha, kerosene, jet fuel, and diesel fuels; wherein therenewable TAG, renewable FFA, and renewable C₁-C₅ FAE include fatty acidunits that have an even number of carbon atoms wherein in the firstproduct, a proportion of hydrocarbons with an odd-number of carbonatoms, cyclic hydrocarbons, or hydrocarbons with an even-number ofcarbon atoms is dependent on an average temperature used during thehydrotreating.

Embodiment 21 provides a method of producing a hydrocarbon product, themethod including: hydrotreating a feedstock including at least one of arenewable triacylglyceride (TAG), renewable fatty acid (FFA), renewablefatty acid C₁-C₅ alkyl ester (C₁-C₅ FAE), or a mixture thereof, in thepresence of a nonsulfided hydrotreating catalyst, to produce a firstproduct including hydrocarbons.

Embodiment 22 provides the apparatus or method of any one or anycombination of Embodiments 1-21 optionally configured such that allelements or options recited are available to use or select from.

1. A method of producing a hydrocarbon product, the method comprising:hydrotreating a feedstock comprising at least one of a renewabletriacylglyceride (TAG), renewable fatty acid, renewable fatty acid C₁-C₅alkyl ester (C₁-C₅ FAE), and a mixture thereof, in the presence of anonsulfided hydrotreating catalyst, to produce a first productcomprising hydrocarbons, wherein the hydrotreating is performed at atemperature in the range of about 470° to about 530° C. and at apressure in the range of about 750 psig to about 1000 psig; wherein therenewable TAG, renewable FFA, and renewable C₁-C₅ FAE comprise fattyacid units that have an even number of carbon atoms; wherein in thefirst product, a proportion of hydrocarbons with an odd-number of carbonatoms, cyclic hydrocarbons, or hydrocarbons with an even-number ofcarbon atoms is dependent on the temperature used during thehydrotreating.
 2. The method of claim 1, wherein greater than 90 mol %of the fatty acid groups in the renewable TAG, renewable FFA, andrenewable C₁-C₅ FAE have an even number of carbon atoms.
 3. The methodof claim 1, further comprising controlling the temperature duringhydrotreating to be a higher temperature, such that in the first productthe ratio of hydrocarbons having an odd-number of carbon atoms tohydrocarbons having an even-number of carbon atoms is higher, or theratio of cyclic hydrocarbons to hydrocarbons having an even-number ofcarbon atoms is higher, as compared to a corresponding ratio obtainedwherein the temperature used during hydrotreating is controlled to be alower temperature.
 4. The method of claim 1, further comprisingcontrolling the temperature during hydrotreating to be a lowertemperature, such that in the first product the ratio of hydrocarbonshaving an odd-number of carbon atoms to hydrocarbons having aneven-number of carbon atoms is lower, or the ratio of cyclichydrocarbons to hydrocarbons having an even-number of carbon atoms islower, as compared to a corresponding ratio obtained wherein thetemperature used during hydrotreating is controlled to be a highertemperature.
 5. The method of claim 1 wherein the nonsulfidedhydrotreating catalyst comprises at least one metal selected from Groups6, 8, 9, and 10 of the periodic table.
 6. The method of claim 5, whereinthe hydrotreating catalyst comprises molybdenum (Mo).
 7. The method ofclaim 6, wherein in the first product, a proportion of at least one ofparaffins resulting from cracking processes or iso-paraffins is greateras compared to a corresponding proportion of at least one of paraffinsresulting from cracking processes or iso-paraffins obtained when thehydrotreating catalyst has less or no molybdenum.
 8. The method of claim5 wherein the hydrotreating catalyst comprises nickel (Ni).
 9. Themethod of claim 8, wherein in the first product, a proportion ofhydrocarbons having an odd number of carbon atoms is greater as comparedto a proportion of hydrocarbons having an odd number of carbon atomswhen the hydrotreating catalyst has less or no nickel.
 10. The method ofclaim 5 wherein the hydrotreating catalyst comprises at least one metalselected from the group consisting of palladium (Pd), platinum (Pt),nickel (Ni), and combinations thereof.
 11. The method of claim 5 whereinthe hydrotreating catalyst comprises nickel and molybdenum or cobalt andmolybdenum.
 12. The method of claim 5 wherein the hydrotreating catalystfurther comprises a support selected from alumina, silica, andcombinations thereof.
 13. The method of claim 1 wherein the TAG in thefeedstock is derived from at least one of plants, animals, algae, othermicroorganisms, or combinations thereof.
 14. The method of claim 1wherein the renewable fatty acid in the feedstock is derived fromhydrolysis of a renewable TAG.
 15. The method of claim 1 wherein therenewable C₁-C₅ FAE in the feedstock is derived from a renewable TAG.16. The method of claim 1 further comprising subjecting the firstproduct to at least one process selected from isomerization, cracking,and aromatization to produce a second product suitable for use as agasoline, naphtha, kerosene, jet fuels, or diesel fuels.
 17. The methodof claim 1 wherein the first product comprises greater than 50 wt %saturated and aromatic hydrocarbons.
 18. A method of producing atransportation fuel, the method comprising: hydrotreating a feedstockcomprising at least one of a renewable triacylglyceride (TAG), renewablefatty acid, renewable fatty acid C₁-C₅ alkyl ester (C₁-C₅ FAE), and amixture thereof, in the presence of a nonsulfided hydrotreatingcatalyst, to produce a first product comprising hydrocarbons, whereinthe hydrotreating is performed at a temperature in the range of about470° to about 530° C. and at a pressure in the range of about 750 psigto about 1000 psig; and subjecting the first product to at least oneprocess selected from aromatization, cracking, and isomerization, toproduce a second hydrocarbon product selected from gasoline, naptha,kerosene, jet fuel, and diesel fuels; wherein the renewable TAG,renewable FFA, and renewable C₁-C₅ FAE comprise fatty acid units thathave an even number of carbon atoms; wherein in the first product, aproportion of hydrocarbons with an odd-number of carbon atoms, cyclichydrocarbons, or hydrocarbons with an even-number of carbon atoms isdependent on the temperature used during the hydrotreating.
 19. A methodof producing a hydrocarbon product, the method comprising: hydrotreatinga feedstock comprising at least one of a renewable triacylglyceride(TAG), renewable fatty acid (FFA), renewable fatty acid C₁-C₅ alkylester (C₁-C₅ FAE), and a mixture thereof, in the presence of anonsulfided hydrotreating catalyst, to produce a first productcomprising hydrocarbons, wherein the hydrotreating is performed at atemperature in the range of about 470° to about 530° C. and at apressure in the range of about 750 psig to about 1000 psig.